AbstractCodec (ESAPI 2.5.3.1 API)

java.lang.Object
- org.owasp.esapi.codecs.AbstractCodec<T>

Type Parameters:

T -

All Implemented Interfaces:

Codec<T>

Direct Known Subclasses:

AbstractCharacterCodec, AbstractIntegerCodec
```
public abstract class AbstractCodec<T>
extends Object
implements Codec<T>
```
The Coded interface defines a set of methods for encoding and decoding application level encoding schemes, such as HTML entity encoding and percent encoding (aka URL encoding). Codeds are used in output encoding and canonicalization. The design of these codecs allows for character-by-character decoding, which is necessary to detect double-encoding and the use of multiple encoding schemes, both of which are techniques used by attackers to bypass validation and bury encoded attacks in data.
Be sure to see the several WARNINGs associated with the detailed method descriptions. You will not find that in the "Method Summary" section of the javadoc because that only shows the intial sentence.

Since:

June 1, 2007

Author:

Jeff Williams (jeff.williams .at. aspectsecurity.com) Aspect Security

See Also:

Encoder

Constructor Summary

Constructors
Constructor and Description

AbstractCodec()
Default constructor

Constructors
Constructor and Description
`AbstractCodec()` Default constructor

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`containsCharacter(char c, char[] array)` Utility to search a char[] for a specific char.
`T`	`decodeCharacter(PushbackSequence<T> input)` Returns the decoded version of the next character from the input string and advances the current character in the `PushbackSequence`.
`String`	`encode(char[] immune, String input)` Encode a String so that it can be safely used in a specific context.
`String`	`encodeCharacter(char[] immune, char c)` To prevent accidental footgun usage and calling `encodeCharacter( char[], int)` when called with `char` and `char` is first silently converted to `int` and then the unexpected method is called.
`String`	`encodeCharacter(char[] immune, Character c)` Default implementation that should be overridden in specific codecs.
`String`	`encodeCharacter(char[] immune, int codePoint)` Default codepoint implementation that should be overridden in specific codecs.
`String`	`getHexForNonAlphanumeric(char c)` Lookup the hex value of any character that is not alphanumeric.
`String`	`getHexForNonAlphanumeric(int c)` Lookup the hex value of any character that is not alphanumeric.
`String`	`toHex(char c)` Convert the `char` parameter to its hexadecimal representation.
`String`	`toHex(int c)` Convert the `int` parameter to its hexadecimal representation.
`String`	`toOctal(char c)` Convert the `char` parameter to its octal representation.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.owasp.esapi.codecs.Codec
decode

- Constructor Detail
  - AbstractCodec
```
public AbstractCodec()
```
    Default constructor
- Method Detail
  - encode
```
public String encode(char[] immune,
                     String input)
```
    Encode a String so that it can be safely used in a specific context.
    WARNING!! Character based Codecs will only handle the byte range of 0-65535 (0x0-0xffff). Passing any data represented by a higher numerical value will result in a downcast thus destroying the original data with undefined results.
    Also, if you are implementing an Integer based codec, these will be silently discarded based on the return from Character.isValidCodePoint( int ). This is the preferred behavior moving forward.
    
    Specified by:
    
    encode in interface Codec<T>
    
    input - the String to encode
    
    Returns:
    
    the encoded String
  - encodeCharacter
```
public String encodeCharacter(char[] immune,
                              Character c)
```
    Default implementation that should be overridden in specific codecs.
    WARNING!!!! Passing a standard char rather than Character to this method will resolve to the encodeCharacter( char[], char ) method, which will throw an IllegalArgumentException instead. YOU HAVE BEEN WARNED!!!!
    
    Specified by:
    
    encodeCharacter in interface Codec<T>
    
    Parameters:
    
    immune - array of chars to NOT encode. Use with caution.
    
    c - the Character to encode
    
    Returns:
    
    the encoded Character
  - encodeCharacter
```
public String encodeCharacter(char[] immune,
                              char c)
```
    To prevent accidental footgun usage and calling encodeCharacter( char[], int) when called with char and char is first silently converted to int and then the unexpected method is called.
    
    Throws:
    
    IllegalArgumentException - to indicate that you called the incorrect method.
  - encodeCharacter
```
public String encodeCharacter(char[] immune,
                              int codePoint)
```
    Description copied from interface: Codec
    
    Default codepoint implementation that should be overridden in specific codecs.
    
    Specified by:
    
    encodeCharacter in interface Codec<T>
    
    codePoint - the integer to encode
    
    Returns:
    
    the encoded Character
  - decodeCharacter
```
public T decodeCharacter(PushbackSequence<T> input)
```
    Description copied from interface: Codec
    
    Returns the decoded version of the next character from the input string and advances the current character in the PushbackSequence. If the current character is not encoded, this method MUST reset the PushbackString.
    
    Specified by:
    
    decodeCharacter in interface Codec<T>
    
    Parameters:
    
    input - the Character to decode
    
    Returns:
    
    the decoded Character
  - getHexForNonAlphanumeric
```
public String getHexForNonAlphanumeric(char c)
```
    Lookup the hex value of any character that is not alphanumeric.
    
    Specified by:
    
    getHexForNonAlphanumeric in interface Codec<T>
    
    Parameters:
    
    c - The character to lookup.
    
    Returns:
    
    return null if alphanumeric or the character code in hex.
  - getHexForNonAlphanumeric
```
public String getHexForNonAlphanumeric(int c)
```
    Lookup the hex value of any character that is not alphanumeric.
    
    Specified by:
    
    getHexForNonAlphanumeric in interface Codec<T>
    
    Parameters:
    
    c - The character to lookup.
    
    Returns:
    
    return null if alphanumeric or the character code in hex.
  - toOctal
```
public String toOctal(char c)
```
    Description copied from interface: Codec
    
    Convert the char parameter to its octal representation.
    
    Specified by:
    
    toOctal in interface Codec<T>
    
    Parameters:
    
    c - the character for which to return the new representation.
    
    Returns:
    
    the octal representation.
  - toHex
```
public String toHex(char c)
```
    Description copied from interface: Codec
    
    Convert the char parameter to its hexadecimal representation.
    
    Specified by:
    
    toHex in interface Codec<T>
    
    Parameters:
    
    c - the character for which to return the new representation.
    
    Returns:
    
    the hexadecimal representation.
  - toHex
```
public String toHex(int c)
```
    Description copied from interface: Codec
    
    Convert the int parameter to its hexadecimal representation.
    
    Specified by:
    
    toHex in interface Codec<T>
    
    Parameters:
    
    c - the character for which to return the new representation.
    
    Returns:
    
    the hexadecimal representation.
  - containsCharacter
```
public boolean containsCharacter(char c,
                                 char[] array)
```
    Utility to search a char[] for a specific char.
    
    Specified by:
    
    containsCharacter in interface Codec<T>
    
    Returns:
    
    True if the supplied array contains the specified character. False otherwise.

Class AbstractCodec<T>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface org.owasp.esapi.codecs.Codec

Constructor Detail

AbstractCodec

Method Detail

encode

encodeCharacter

encodeCharacter

encodeCharacter

decodeCharacter

getHexForNonAlphanumeric

getHexForNonAlphanumeric

toOctal

toHex

toHex

containsCharacter